Photolithographic patterning is a well-established technology in the manufacturing processes of various kinds of semiconductor devices and liquid crystal display panels. According to photolithographic patterning, a photosensitive resist composition is first coated onto a surface of a substrate to form a photoresist layer. The photoresist layer is then exposed to radiation, such as ultraviolet light or electron beam, so that some portions of the photoresist are impacted by radiation while other portions of the photoresist are not impacted by the radiation. Subsequently, the photoresist is subjected to a developer solution, which selectively removes either the impacted or non-impacted portions of the photoresist. If the photoresist is a positive photoresist, the impacted portions are selectively removed; if the photoresist is a negative photoresist, the non-impacted portions are selectively removed. The photoresist material remaining after development shields or masks the regions of the substrate from subsequent etch or implant operations.
The development process of photoresist is conducted to provide the pattern which will serve as a mask for etching, ion-implantation or lift-off, for example, on the substrate. One of the goals of an effective development process is minimizing pattern distortion. Pattern distortion is the result of many factors, two primary ones being resist roughness and surface tension. Surface tension pulls down the walls of the photoresist (also known as toppling) during the rinsing and drying steps of the development process, therefore destroying the pattern that was originally formed. As illustrated in FIG. 1, for example, fine lines formed by photoresist are used to pattern electrical connections onto a blanket layer, for example a blanket metal layer. When the walls of the photoresist topple, the connections cannot be properly placed onto the blanket metal layer. Toppling of the photoresist causes damage to the substrate, is costly as substrates must be scrapped, and time consuming.
Accordingly, there is a need for a photoresist stabilizing solution that will reduce or eliminate the toppling of the photoresist, therefore improving manufacturing efficiency and production yields. Also needed are methods of increasing the mechanical and structural strength of photoresist patterns to prevent deformation, profile abnormalities or collapse by liquid surface tension forces in high density semiconductor fabrication.